A Tamil asylum seeker fears he will die in a Melbourne detention centre after being diagnosed with leukaemia, during his almost decade-long fight for refugee status.

Refugee advocates have demanded Sivaguru Navanitharasa, known to his friends as "Rajan", be released so he can access regular medical treatment.

The 45 year-old has been in detention since 2009 and was diagnosed with the potentially fatal blood cancer in March.

Doctors for Refugees president Barri Phatarfod said Rajan’s declining health would be made worse by his detainment.

“Those diagnosed with leukaemia are more susceptible to infections, anemia and bleeding,” Dr Phatarfod said.

“A combination of mental stress of being in detention, substandard food and conditions, and antidepressants may aggravate his case.”

Rajan was granted refugee status by the Australian Government in 2010, but that decision was overturned by the Australian Security Intelligence Organisation (ASIO) after they deemed him to be a potential risk to the community.

He then submitted a new migrant protection application in a bid to prove he was not a threat to anyone, but it was rejected.

Tamil Refugee Council spokesperson Aran Mylvaganam said Rajan has not received adequate medical care and he would not be reassessed by a doctor for at least three months.

“Rajan is devastated. Previously he never wanted to speak about his case despite being in detention,” Mr Mylvaganam said.

“The fact that he may die in detention has forced him to speak out.”

Rajan fled Sri Lanka in the midst of a civil war and genocidal threats being made on the Liberation Tigers of Tamil Eelam.

When his most recent application for asylum was rejected nine months ago, Rajan escalated his case to the Administrative Appeals Tribunal. He is yet to receive a response.

Mr Mylvaganam said the Australian Government was not communicating with the Tamil Refugee Council.

“Under this government it has been difficult for us to get even a meeting with the immigration minister. We have a communication issue with this government,” he said.

“We are not hopeful that things will be better until there is a change of government.”

Matt Di Lorenzo, a social worker who lists detainees among his clientele, said Rajan's situation was “concerning”.

“It doesn’t take a social worker to know that nine years of being locked up with uncertainty is detrimental to physical and mental health,” Mr Di Lorenzo said.

“It took them (Australian Government) six years to reverse his security clearance, another two years to reprocess his refugee status, and another nine months for his tribunal appeal,” he said.

Mr Di Lorenzo has started an online petition, which calls for Rajan's release.

During the Sri Lankan civil war, there was an upsurge of immigration from Sri Lanka to Australia with the majority of asylum seekers being Tamils.

In 2019, 6.7 per cent of detainees in Australia are from Sri Lanka and more than 22 per cent of all detainees have been held in detention facilities for more than two years, according to statistics from the Department of Home Affairs.

The Tamil Refugee Council has also started a campaign titled #FreeRajan, to highlight his plight.

The Department of Home Affairs was contacted, but a spokesperson said it would not provide comment to student journalists.